PoliSci folks have been pointing out forever that voting is irrational. The odds that your vote will make any difference are miniscule, so taking the time and effort to fill out the form (much less learn about the issues) is a losing proposition.
It seems that people believe in the power of collective action.
Or maybe they just want to get laid:
The Voting Paradox Explained! Why People Vote… — The Monkey Cage.